Introduction
In a 2014 investigation, The Washington Post reported that the FBI
had been under-counting fatal police shootings by more than half. An
eighteen year-old Michael Brown was killed by police in St. Louis,
Missouri, shining a light on the issue of police brutality in the United
States. Relying on news, social media, and police reports, the
Washington Post compiled a comprehensive list of police shootings from
2015 to 2022 to amend the issue of under-counting police killings of
civilians. Police brutality stems from a lack of accountability. The
police force is consistently protected from the consequences of
violence, regardless of the use of such tools of accountability as
police body cameras. We studied the use of body cameras in police
shootings to understand whether the use of body cameras was more common
in one state over another. More specifically, we asked: within our data
set of 6,574 observations of police shootings from 2015 to 2022 in the
United States, is there a correlation between the U.S. state of
observation and whether a body camera was turned on during the shooting?
We found that the use of body cameras during fatal police shootings
certainly varies by state, pointing to the conclusion that state policy
plays a role in whether body cameras are turned on during active police
duty.
This data set includes information on every fatal police shooting
from January 1, 2015 to the present. It is updated regularly by the
Washington Post. Some of the Post’s key findings from the data set
include:
Overall, police nationwide kill approximately 1,000 civilians
annually.
Black people are killed by police at a higher rate than White
people. In absolute numbers, the White population is killed most often
by police. Black people, accounting for less than 13 percent of the
population, are killed more than twice the rate of White
people.
The majority of victims are male and between the ages of 20 and
40 years.
Police shootings occur in every state. In cities, they are more
frequent. The states with the highest rates of shootings (considering
state population) are New Mexico, Alaska, and Oklahoma.
These findings are the result of previous research by the Washington
Post. One of the data set’s limitations is the absence of data on
populations at the time of the observation. This information would be
valuable for any type of racial injustice analysis. The research we
gathered through the EDA began with very basic analyses:





These basic univariate analyses were created to better understand the
data set and to identify any interesting patterns that emerged. We began
doing more complex multivariate analyses and noting any interesting
findings:
Hover over the map below to see the breakdown of fatal police
shootings, divided by the race of the victim. We looked at the total
number of deaths in each state by race and following are some of the
insights:
We see that the state with the highest level of victims of police
violence is California with a total of 885 victims, followed by Texas
with a total of 553 and then Florida with 427.
These results are consistent with the populations of these
states, with the highest being California, then Texas, and then
Florida.
We also observe that the highest number of deaths is for Hispanic
people in California, whereas in Texas and Florida there are more fatal
shootings of White people.
Then we looked at the age of the suspect shot, as well as their race.
We made the following observations:
We see from the boxplot below that the median age for Black
people that have been killed by police is 29 years.
White people have a relatively higher median age of 35 years
whereas Asian people have the highest median age of around 38
years.

If we look at the age of each victim against the status of their
mental health, we can make the following observation: signs of mental
illness appear more frequently within the 30s age range while death by
police for people age 50 and above are more common for people showing
signs of mental illness.

We also looked at the death by race and gender, coming up with the
following insight: individuals across all races that were shot and
killed by police were more often men.

We then looked at the distribution of deaths by race and the top 5
armed categories. We discovered that around 9% of the Black victims were
unarmed whereas only approximately 6% of the White victims were unarmed.
Guns were the most used weapon across all races except for Asian
individuals. Asian victims were more often wielding knives.
The following graph illustrates the deaths per year by race from
2015-2022:

We looked at the distribution of deaths by suspects’ race and whether
they were trying to flee or not. The following are some of our most
interesting observations:
Only 53% of Black victims shot were not fleeing whereas 71% of
the Asian victims who were shot were not trying to flee.
The car is the most popular method of fleeing among White victims
whereas for Black victims, the most popular method of fleeing was by
foot.
After performing all of this exploratory data analysis, we decided we
wanted to ask a state- and region-based question. Performing a more
comparative analysis using this data set could help us understand why
police shootings occur in some states over others. This required us to
divide the data in a new way. For data visualization purposes, we chose
to divide each state into regions. However, our main focus will rely on
state-by-state comparative analysis. The following regional subsets
include:
| California |
New Mexico |
Illinois |
Georgia |
New York |
| Washington |
Arizona |
Wisconsin |
Alabama |
Rhode Island |
| Oregon |
Texas |
Indiana |
Mississippi |
Maryland |
| Nevada |
Oklahoma |
Michigan |
Louisiana |
Vermont |
| Idaho |
Hawaii |
Minnesota |
Tennessee |
Pennsylvania |
| Utah |
- |
Missouri |
North Carolina |
Maine |
| Montana |
- |
Iowa |
South Carolina |
New Hampshire |
| Colorado |
- |
Kansas |
Florida |
New Jersey |
| Wyoming |
- |
North Dakota |
Arkansas |
Connecticut |
| Arkansas |
- |
South Dakota |
West Virginia |
Massachusetts |
| Arkansas |
- |
Nebraska |
DC |
- |
| - |
- |
Ohio |
Virginia |
- |
Fatal shootings in the Northwest United States:
## [1] 1810
Fatal shootings in the Southwest United States:
## [1] 1226
Fatal shootings in the Midwest United States:
## [1] 1080
Fatal shootings in the Southeast United States:
## [1] 1890
Fatal shootings in the Northeast United States:
## [1] 568
After dividing up the data set, we decided to spotlight the body
camera variable. This column in the csv file asked whether the body
camera was turned on or off during the fatal police shooting. The data
was compiled from official police records, completed by the officers on
site. In the Washington Post’s brief article introducing the data set
and examining some of the most interesting findings, there was no
mention of the body camera variable. This provided us an opportunity to
create a relevant, meaningful research project on a little-studied
aspect of police work. Our final research question is as follows:
Within our data set of 6,574 observations of police shootings from
2015 to 2022 in the United States, is there a correlation between the
U.S. state of observation and whether a body camera was turned on during
the shooting?
After performing the technical analysis needed to assert that body
camera use varies by state, there is still valuable information we need
to find a link between state policy on body cameras and the rate at
which body cameras are turned on during fatal shootings. The remainder
of this paper will attempt to bridge quantitative analysis using the
Washington Post data set with qualitative information on state body
camera policy. We will also look into funding by state for police work
to see if there is a strong correlation between the amount of police
funding and the rate at which body cameras are turned on during fatal
shootings.
Part I: Quantitative Analysis
Number of fatal shootings where the body camera was on:
## body_camera n
## 1 TRUE 947
Number of fatal shootings where the body camera was off:
## body_camera n
## 1 FALSE 5627
We created some figures to visualize body camera use by state and
region. In the below bar graph, TRUE signifies a police body camera that
was on, while FALSE indicates the body camera was off:

A very important variable allowed us to study body camera use
variation by state. This variable is stbcp, or the proportion of
shootings when a police body camera was turned on by state. We first
checked our data for normality. Because the plot below is relatively
linear, we concluded this data is close enough to normality for our
purposes.

This scatter plot below illustrates the comparative power of stbcp.
Each point on the graph depicts a state’s proportion of shootings where
the police body camera was turned on during the incident. These data
points also show an interesting regional variation. For example, we can
see that there is very little variation in Southwest, and many
differences among states in the Midwest.

We performed a chi-square test to understand whether there is a
significant difference between the proportions of body cameras being on
during fatal shootings each state.
\(H_{0}\): There is no significant
differences between US States in the proportion of body cameras being
turned on during police shootings
\(H_{A}\): There is a significant
difference between US State in the proportion of body cameras being
turned on during police shootings
Significance Level: \(\alpha =
0.05"\)
## Min. 1st Qu. Median Mean 3rd Qu. Max.
## 0.000 0.101 0.133 0.144 0.183 0.409
##
## Pearson's Chi-squared test
##
## data: contable
## X-squared = 3e+05, df = 2300, p-value <2e-16
With a p-value of less 2e-16, we easily pass our significance level
of alpha=0.05 and have shown that there exists significant differences
between different states’ proportions of body camera usage during fatal
police shootings. The challenge now becomes, what is causing this
variation in state use of body cameras during active police work? We
intend to delve into the reasons why there are differences and research
what factors may explain these differences between states. This will
require understanding state laws and policies regarding the use of
police body cameras. We must also understand the police force
consequences for turning off body cameras during police activity in
different states.
Studying the use of body cameras in police work is an important topic
of study for data-driven policy research in the United States. We hope
to be able to apply this correlation between the U.S. state of
observation and whether the body camera was on or off during the
shooting to state policy on body cameras during police work.
Part II: Qualitative Analysis
We have the visualization, as well as the Chi-square test, to confirm
that there is a significant difference in stbcp (the proportion of
shootings when a police body camera was turned on by state). Let us now
look at the rankings by state of stbcp, from most to least likely of
having a body camera on during a police shooting.
| DC |
0.409 |
Vermont |
0.333 |
Nevada |
0.330 |
| Utah |
0.307 |
Maryland |
0.277 |
Connecticut |
0.238 |
| Iowa |
0.225 |
Hawaii |
0.212 |
Nebraska |
0.200 |
| Rhode Island |
0.200 |
California |
0.188 |
Idaho |
0.185 |
| Indiana |
0.185 |
Oklahoma |
0.179 |
Arizona |
0.161 |
| Alabama |
0.160 |
New York |
0.160 |
New Mexico |
0.159 |
| South Carolina |
0.156 |
New Hampshire |
0.150 |
Illinois |
0.148 |
| Wisconsin |
0.146 |
Virginia |
0.144 |
North Dakota |
0.143 |
| North Carolina |
0.134 |
Michigan |
0.133 |
Minnesota |
0.133 |
| Ohio |
0.131 |
Texas |
0.131 |
Kansas |
0.130 |
| Delaware |
0.125 |
Colorado |
0.123 |
Louisiana |
0.119 |
| Washington |
0.103 |
Kentucky |
0.103 |
Tennessee |
0.101 |
| Montana |
0.100 |
New Jersey |
0.100 |
Florida |
0.0995 |
| Georgia |
0.0988 |
Alaska |
0.0952 |
Arkansas |
0.0787 |
| Oregon |
0.069 |
West Virginia |
0.0678 |
South Dakota |
0.0625 |
| Missouri |
0.037 |
Pennsylvania |
0.0352 |
Maine |
0.000 |
| Wyoming |
0.000 |
|
|
|
|
Here we can see that the states with the highest number of
observations where the police body camera was turned on include DC,
Vermont, and Nevada. The states with the lowest number include
Pennsylvania, Maine, and Wyoming–Maine and Wyoming having no recorded
police shooting where a body camera was turned on. Let us now do a
deep-dive into state policy on body cameras for these six states.
The four most common state laws that govern body camera usage will
guide our analysis of individual state policy. These laws are as
follows:
Either a study group or pilot program on the use of body-worn
cameras was used or was recommended by law.
Laws dictate where, when, and how, body cameras can be used
during police activity.
The public has access to police footage.
There is a prescribed amount of time videos are stored before
being discarded.
Although there are other laws which apply to body cameras, these are
the four major laws specific to their use. We hypothesize that the
applications of these laws will line up well with the stbcp scores we
see for each state. We will also include information on the amount of
money spent on policing per capita each state.
District of Columbia
DC stbcp score:
## [1] 0.409
While DC does not have any requirement for a study group or pilot
program, it does possess the three other laws. Before being issued a
body camera, officers are required to be trained in their use. The only
situation in which a police officer is prohibited from turning on his
body camera is when engaging with students and minors. The 2015
Body-Worn Camera Program Amendment Act allows the mayor to release
police footage for cases of public interest. The act also gives the
police up to 40 days to respond to all Freedom of Information requests
from the public to hand over footage (which of course police can respond
that the footage is inaccessible). Finally, the police may retain
footage for no more than 90 days unless the recordings serve as
evidence.
DC spends $965 per capita on policing, the highest of any state in
the United States by about double. This likely provides DC police with
ample funds for police body cameras and their required training.
Vermont
Vermont stbcp score:
## [1] 0.333
Unlike in DC, Vermont did require its State Law Enforcement Advisory
Board to produce a report using research methods like study groups to
recommend procedures for the use of body cameras, storage time, and
exemptions for the Public Records Act. However, there is still no law
set in place which governs where and when police may use or not use
their body cameras. Vermont’s Law Enforcement Advisory Board Model
Policy states that open records requests apply to all body camera
recordings. If disputes arise between a public requester and the police
department, the recording will be maintained until the dispute is
settled. Finally, Vermont has very strict laws for the erasure of police
recording. Only with permission from the State Archivist or under law
can police body camera footage be erased.
Vermont ranks very low on police spending with only $351 per capita
put towards policing.
Nevada
Nevada stbcp score:
## [1] 0.33
Similar to DC, Nevada has no legal requirement for a study group or
pilot program like Vermont does. It does have pretty strict laws on the
use of body cameras during active police work. Any officer who is
frequently out in the field must be equipped with a body camera while on
duty. Under law, the officer is required to turn on the camera when
responding to a call or engaging in any confrontation between the police
and the public. Under Nev.Rev.Stat. § 289.830, the camera may not be
turned off until the investigation is complete. Any recording is subject
to a public records request, but is only approved to be released on a
case-by-case basis. The only requirement for video storage is that all
recordings must be saved for at least fifteen days since the time of the
incident.
Nevada spends $477 per capita on policing. Among the 50 states plus
DC, it ranks second in the best allocation of police resources, only
behind Florida.
Pennsylvania
Pennsylvania stbcp score:
## [1] 0.0352
Pennsylvania requires municipalities to establish their own written
policies regarding training on the proper use of body cameras, when the
body cameras should be turned on, and all protocols for disciplinary
conduct when such policies are violated. There is no state law governing
how, where, and when body cameras are used. Civilians may request access
to footage, and police are given 30 days from the time they recieve the
request to either fulfill or deny it. However, all recordings containing
evidence, information regarding a criminal charge, or confidential
victim information are exempt from public requests. Footage is only
saved if there is an active public request for it or it provides
evidentiary value.
Pennsylvania spends $335 per capita on policing, which is the lowest
we have seen in this analysis thus far.
Maine
Maine stbcp score:
## [1] 0
Maine has zero laws governing the use of body cameras. In 2021, the
Maine State Police began the process of allocating funds for the
introduction of body cameras in police work. Its stbcp is 0 simply
because police do not use body cameras at all.
The state spends only $244 per capita on policing. Again, this is the
lowest amount of money spent on policing we have seen.
Wyoming
Wyoming stbcp score:
## [1] 0
Wyoming’s sole law on access to police recordings is to prohibit
public access except to the person in the recording. Officers are
equipped with body cameras as of 2021.
The state spends $400 per capita on policing. Both Wyoming and Maine
are ranked close to last on policing allocation of funds.
If we are comparing the top 3 states for stbcp with the worst 3
states, as we have above, clearly there is a trend showing that rigorous
state policy and funding corresponds with higher rates of body cameras
turned on during fatal shootings. Now let’s look at all states in
relation to these four laws governing the use of body cameras and state
funding for policing.
| DC |
0.409 |
3 |
$965 |
| Vermont |
0.333 |
3 |
$351 |
| Nevada |
0.330 |
3 |
$477 |
| Utah |
0.307 |
3 |
$289 |
| Maryland |
0.277 |
4 |
$503 |
| Connecticut |
0.238 |
3 |
$363 |
| Iowa |
0.225 |
0 |
$290 |
| Hawaii |
0.212 |
1 |
$384 |
| Nebraska |
0.200 |
4 |
$302 |
| Rhode Island |
0.200 |
0 |
$485 |
| California |
0.188 |
4 |
$564 |
| Idaho |
0.185 |
1 |
$302 |
| Indiana |
0.185 |
3 |
$238 |
| Oklahoma |
0.212 |
2 |
$288 |
| Arizona |
0.161 |
1 |
$401 |
| Alabama |
0.160 |
0 |
$296 |
| New York |
0.160 |
3 |
$570 |
| New Mexico |
0.159 |
3 |
$365 |
| South Carolina |
0.156 |
2 |
$275 |
| New Hampshire |
0.150 |
4 |
$362 |
| Illinois |
0.148 |
1 |
$448 |
| Wisconsin |
0.146 |
3 |
$330 |
| Virginia |
0.144 |
4 |
$316 |
| North Dakota |
0.143 |
1 |
$337 |
| North Carolina |
0.134 |
2 |
$345 |
| Michigan |
0.133 |
2 |
$293 |
| Minnesota |
0.133 |
2 |
$428 |
| Ohio |
0.131 |
4 |
$347 |
| Texas |
0.131 |
3 |
$323 |
| Kansas |
0.130 |
1 |
$363 |
| Delaware |
0.125 |
4 |
$401 |
| Colorado |
0.123 |
3 |
$402 |
| Louisiana |
0.119 |
2 |
$326 |
| Washington |
0.103 |
4 |
$334 |
| Kentucky |
0.103 |
1 |
$183 |
| Tennessee |
0.101 |
1 |
$335 |
| Montana |
0.100 |
0 |
$350 |
| New Jersey |
0.100 |
3 |
$449 |
| Florida |
0.0995 |
3 |
$470 |
| Georgia |
0.0988 |
3 |
$287 |
| Alaska |
0.0952 |
0 |
$555 |
| Arkansas |
0.0787 |
2 |
$244 |
| Oregon |
0.069 |
3 |
$376 |
| West Virginia |
0.0678 |
0 |
$254 |
| South Dakota |
0.0625 |
1 |
$259 |
| Missouri |
0.037 |
1 |
$321 |
| Pennsylvania |
0.0352 |
3 |
$335 |
| Maine |
0.000 |
0 |
$244 |
| Wyoming |
0.000 |
1 |
$400 |
Part III: Results and Conclusion
While there does seem to be a trend of higher stbcp scores for states
with more laws on body cameras and more funding for policing, we would
need to perform more technical analysis to assert causality. Looking at
the six case studies (DC, Vermont, Nevada, Pennsylvania, Maine, and
Wyoming), we can easily see that more strict body camera laws and higher
funding for policing correspond with the three states with the highest
stbcp scores. However, when we look further into the list, we see states
like Iowa with 0 laws governing body camera use but with a relatively
high stbcp score. Before we can determine that state policy in DC,
Vermont, and Nevada should be used as a model for body camera policy,
more research is needed to consider all factors that may contribute to
body cameras being turned on during a fatal shooting.
Studying the use of body cameras in police work is an important topic
of study for data-driven policy research in the United States. We hope
to be able to apply this correlation between the U.S. state of
observation and whether the body camera was on or off during the
shooting to state policy on body cameras. The relevancy of studying
fatal shootings cannot be understated in the field of U.S. public
policy. One limitation of this EDA is the lack of research on racial
injustice and proportionality in fatal shootings by race. This will be
an important facet of our future research if we continue to pursue this
research topic.
Part IV: Citations
1,032 people have been shot and killed by police in the past year
(November 10, 2022), The Washington Post. https://www.washingtonpost.com/graphics/investigations/police-shootings-database/
N.G. La Vigne, M. ulle, N. Erondu, D. Lawrence, L. Robin, T.
Meko, B. Chartoff, D. Wood, Police Body-Worn Camera Legislation Tracker
(July 14, 2022), The Urban Institute. https://apps.urban.org/features/body-camera-update/
J. Michtom, US Budget Analysis: Policing and Corrections Spending
by State (October 21, 2022), Money Geek. https://www.moneygeek.com/living/state-policing-corrections-spending/
Wyoming Police Now Equipped with Body Cameras (February 19,
2021), What’s Up Wyoming. https://www.whatsupwyoming.com/2021/02/wyoming-police-now-equipped-with-body-cameras/
What is the Status of Body Cameras in Maine? A Closer Look at the
State’s Laws (2021) Gov QA. https://www.govqa.com/status-of-body-cameras-in-maine/